Natural Hazards

A hazard is a potential threat to human life or property. 

Geophysical- earthquakes, volcanoes, landslides and tsunmais.

Atmopsheric- tropical cyclones, storms, droughts, wildfires.

Hydrological- floods.

Mitigation- this aims to minimise the impacts of future disasters- building flood defences or adding fire resistant roofs.

Preparedness- planning how to respond to the hazard- education, warnings.

Response- how people react when a disaster occurs- emergency services, evaculating people.

Recovery- this is about getting the affected area back to normal- rebuilding hpuses, restoring electricity. 

Convection currents- lower parts of the asthenopshere heat up, vecome less dense and slowly rise. As they move towards the top of the asthenosphere, they cool down, become more dense and slowly sink. These circular movements of semi-molten rock are also called convection currents. They create drag on the base of the tectonic plates, causing them to move. 

Slab pull- at a destrcutive plate margin, the denser crust is forced under the less dense crust. the sinking of the plate pulls the rest of the plate towards the boundary. 

Ridge push- at contstructive plate margins, magma rises to the surface and forms a new crust which is very hot. This heats up the surrounding rocks which expand and rise to the surface of the surrounding crust, forming a slope. The new crust cools and becomes denser, gravity causes the denser rock to move downslope, away from the plate margin. This puts pressure on the tectonic plates, causing them to move apart. This is also known as graviational sliding. 

Sea floor spreadimg occurs when plates move apart. As tectonic plates diverge, magma rises up to fill the gaps created, then cools to form a new crust. Over-time, the new crust is dragged apart and even more new crust forms between it. When this happnes at the plate margin under the sea, the sea floor gets wider. This process is called…